Designing test systems to test large numbers of electronic devices such as semiconductors in a factory environment where each individual device undergoing testing generates a significant thermal load is not easy to accomplish. Examples of such heat generating electronic devices include but are not limited to high-speed microprocessors, laser diodes, and linear high-power amplifiers.
From a semiconductor manufacturer's standpoint, factory floor space often comes at a premium. A testing system that is capable of testing the largest number of semiconductor devices in the smallest factory floor footprint is therefore highly desirable. Removing large amounts of heat from high heat dissipation devices in a very small footprint is problematic, however. Air-cooling electronic devices undergoing testing in order to dissipate heat generated by the electronic devices typically requires large heat sinks with a corresponding large surface area and size. Air-cooled systems such as systems employing fans can simply blow air onto the (Device under Test) DUTs in quickly removable Burn-In-Boards (BIBs) without having to move the fans. DUTs can be any type of electronic device such as a power semiconductor, etc. Fan cooling systems have the drawback of sometimes not being able to dissipate a lot of thermal energy away from the DUT, which presents a problem when testing a large number of electronic devices that give off a large amount of thermal energy during testing.
Liquid-cooling electronic devices undergoing testing on the other hand requires a lower corresponding heat exchanger area than air, and can maintain a more narrow range of burn-in temperatures. However, liquid and refrigerant cooling require heat sinks connected to fixed plumbing that need to make intimate thermal contact with the DUT in a removable and repeatable manner. Previous systems use a complicated mechanism to lower liquid cooled heat sinks onto the DUTs during burn-in and retract the heat sinks after the testing is complete. This requires the heat sinks to be mounted on gimbals or other movable structure to accommodate non-planar DUT surfaces but still maintain fluid lines which adds complexity to the test system.